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行鉴相器中的相位关系
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作者 廖惜春 《电视技术》 北大核心 1989年第7期45-47,共3页
1.从行鉴相器的工作原理分析在行扫描系统中,行鉴相器的输出电压信号U_(AFC)直接控制行振荡管的基极电位,从而控制行振荡频率。这种控制是在静态偏置电压的基础上进行的。鉴相器的动态输出信号正比于行同步脉冲与比较信号(由行逆程脉冲... 1.从行鉴相器的工作原理分析在行扫描系统中,行鉴相器的输出电压信号U_(AFC)直接控制行振荡管的基极电位,从而控制行振荡频率。这种控制是在静态偏置电压的基础上进行的。鉴相器的动态输出信号正比于行同步脉冲与比较信号(由行逆程脉冲积分而得)的相位差。只要这二者有相位差,AFC电路就有一个校正电压输出。图1所示是平衡式鉴相器之一,其中T是分相管。由C_1、C_2、D_1、D_2、R_1和R_2等组成鉴相器。 展开更多
关键词 电视 行扫描系统 监相器 相位 控制
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双向过零鉴相技术与实现 被引量:2
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作者 潘文诚 《电测与仪表》 北大核心 1995年第6期33-35,共3页
本文在论述单向过零鉴相的缺陷后提出前后沿平均鉴相和脉冲中心点鉴相两种双向过零鉴相技术的原理。最后介绍了用8098单片机的HSI部件实现双向过零中心点鉴相进行精密相位测量的方法。
关键词 相技术 监相器 双向过零
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Absolute Measurement Fiber-optic Sensors inLarge Structural Monitoring 被引量:2
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作者 WANG Zhao-ying, WU Xing, TIAN He-bin, LI Shi-chen(College of Precision Instrum.and Optoelectron.Eng., Tianjin University, Tianjin 300072, CHN) 《Semiconductor Photonics and Technology》 CAS 2003年第2期102-106,共5页
The security of civil engineering is an important task due to the economic, social and environmental significance. Compared with conventional sensors, the optical fiber sensors have their unique characteristics.Being ... The security of civil engineering is an important task due to the economic, social and environmental significance. Compared with conventional sensors, the optical fiber sensors have their unique characteristics.Being durable, stable and insensitive to external perturbations,they are particular interesting for the long-term monitoring of civil structures.Focus is on absolute measurement optical fiber sensors, which are emerging from the monitoring large structural, including SOFO system, F-P optical fiber sensors, and fiber Bragg grating sensors. The principle, characteristic and application of these three kinds of optical fiber sensors are described together with their future prospects. 展开更多
关键词 SOFO system F―P fiber―optic sensors fizeau interferometer white―lightcross―correlator fiber bragg sensors large structure monitoring
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ADS-B Anomaly Data Detection Model Based on Deep Learning and Difference of Gaussian Approach 被引量:6
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作者 WANG Ershen SONG Yuanshang +5 位作者 XU Song GUO Jing HONG Chen QU Pingping PANG Tao ZHANG Jiantong 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2020年第4期550-561,共12页
Due to the influence of terrain structure,meteorological conditions and various factors,there are anomalous data in automatic dependent surveillance-broadcast(ADS-B)message.The ADS-B equipment can be used for position... Due to the influence of terrain structure,meteorological conditions and various factors,there are anomalous data in automatic dependent surveillance-broadcast(ADS-B)message.The ADS-B equipment can be used for positioning of general aviation aircraft.Aim to acquire the accurate position information of aircraft and detect anomaly data,the ADS-B anomaly data detection model based on deep learning and difference of Gaussian(DoG)approach is proposed.First,according to the characteristic of ADS-B data,the ADS-B position data are transformed into the coordinate system.And the origin of the coordinate system is set up as the take-off point.Then,based on the kinematic principle,the ADS-B anomaly data can be removed.Moreover,the details of the ADS-B position data can be got by the DoG approach.Finally,the long short-term memory(LSTM)neural network is used to optimize the recurrent neural network(RNN)with severe gradient reduction for processing ADS-B data.The position data of ADS-B are reconstructed by the sequence to sequence(seq2seq)model which is composed of LSTM neural network,and the reconstruction error is used to detect the anomalous data.Based on the real flight data of general aviation aircraft,the simulation results show that the anomaly data can be detected effectively by the proposed method of reconstructing ADS-B data with the seq2seq model,and its running time is reduced.Compared with the RNN,the accuracy of anomaly detection is increased by 2.7%.The performance of the proposed model is better than that of the traditional anomaly detection models. 展开更多
关键词 general aviation aircraft automatic dependent surveillance-broadcast(ADS-B) anomaly data detection deep learning difference of Gaussian(DoG) long short-term memory(LSTM)
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